Traditionally where there has been a need or a desire to transport goods of a volume or mass that is of an impractical size to require the assistance of trucks or other heavy machinery, but large enough to make the goods difficult to carry manually, people have turned to the use of carts, dollies, trolleys, and similar mechanisms for assistance. Two of the more common of such devices are the standard wheelbarrow and shopping cart, both of which have been in widespread use for a considerable length of time. Prior known shopping carts include those that are described under U.S. Pat. Nos. 4,096,920; 4,771,840; 4,020,916; 4,750,578; and 5,064,012, and U.S. design patent Des 309,517.
Where the mass or volume of products or goods sought to be moved is significant, others have proposed the use of a self-propelled or powered cart to transport the goods from place to place. An example of such a powered cart or barrow is found in U.S. Pat. No. 2,918,133. Another example of a powered cart is described by U.S. Pat. No. 3,266,813 which concerns a mobile garden and refuge cart for safe and sanitary storage, clean-up and pick-up services. Other carts or transportation devices are described and discussed in U.S. Pat. Nos. 3,485,314; 3,791,470; 4,137,984; and, 4,203,609.
While the powered carts or transportation devices developed by others, including those described in the U.S. patents listed above, have proven useful to assist individuals in transporting materials from place to place, they suffer from the inherent limitation of being particularly adapted and designed for a single specific use only. For example, while a powered wheelbarrow, such as that described in U.S. Pat. No. 2,918,133, may be useful in transporting sand, bricks, or other materials on a construction site, it offers little assistance to an elderly person walking home with a significant volume of groceries. Similarly, a powered grocery shopping cart would be of little use on a construction site, to an individual wishing to transport bags of fertilizer or other supplies when engaged in gardening activities, or to someone moving luggage through an airport terminal. Existing “powered” carts or trolleys are designed with specific end uses in mind making it impractical, if not in many cases impossible, to adapt or utilize the devices for applications other than the particular purposes for which they were constructed. The size, weight and complexity of many such prior art devices also makes them uneconomical and/or impractical for use by consumers outside of industrial applications. In addition, currently available powered carts tend to operate at fixed speeds and are not accommodating to different individuals who may walk at different rates.